[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Conditions](https://durgical.com/en/conditions/) › Leber hereditary optic neuropathy (LHON)

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# Leber hereditary optic neuropathy (LHON)

Leber optic neuropathy is a maternally inherited mitochondrial disease that causes sudden, painless loss of central vision, mostly in young men.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Optic nerve](https://durgical.com/en/anatomy/optic-nerve/)
- [Retina](https://durgical.com/en/anatomy/retina/)
- [Optic disc](https://durgical.com/en/anatomy/optic-disc/)
- [Optic chiasm](https://durgical.com/en/anatomy/optic-chiasm/)
- [Macula](https://durgical.com/en/anatomy/macula/)
- [Visual cortex](https://durgical.com/en/anatomy/cuneus/)

## In biochemistry

- [Electron transport chain and oxidative phosphorylation: Step 1 · Complex I (NADH:ubiquinone oxidoreductase)](https://durgical.com/en/biochemistry/pathways/electron-transport-chain-and-oxidative-phosphorylation/#paso-1)
- [Complex I (NADH dehydrogenase)](https://durgical.com/en/biochemistry/enzymes/complex-i/)

## Why it happens

- [Mechanisms of cell injury: ATP, mitochondria, calcium, membranes and DNA](https://durgical.com/en/general-pathology/mechanisms-of-cell-injury-atp-mitochondria-calcium-membranes-and-dna/)

## What it is

Death of retinal ganglion cells and their axons in the [optic nerve](https://durgical.com/en/anatomy/optic-nerve/) from a complex I defect, causing subacute loss of central vision in both eyes.

## Who gets it

It affects 1 in 30,000–50,000 people in the populations studied (northeast England, Finland); there are no figures for Colombia. It is much more common in men and usually starts between ages 15 and 35.

## Causes

- Mitochondrial DNA variants in complex I genes: MT-ND4 (m.11778G>A, the most common), MT-ND1 (m.3460G>A) and MT-ND6 (m.14484T>C)
- Maternal inheritance with incomplete penetrance: many carriers never lose vision

## Risk factors

- Male sex
- Affected relatives on the mother's side
- Smoking
- Heavy alcohol use

## Pathophysiology

The variants reduce complex I's ability to pass electrons from NADH to ubiquinone: ATP falls and reactive oxygen species rise. Retinal ganglion cells have long axons that are unmyelinated inside the eye, with huge energy needs, especially those of the papillomacular bundle, which carries central vision. They degenerate and leave a central scotoma. Why men are affected more and why only some carriers fall ill is not fully known (estrogen and environment play a part).

## Symptoms and signs

- Painless central blurring in one eye
- The other eye follows weeks or months later
- Central or centrocaecal scotoma
- Loss of colour vision
- Some patients have arrhythmias or neurological symptoms (“LHON plus”)

## Red flags

- Subacute central vision loss in a young person with eye pain: think of optic neuritis first
- Vision loss with other neurological deficits
- Signs of optic nerve or chiasm compression

## Diagnosis

**Clinical**
Painless, sequential central vision loss in a young person with a maternal history; in the acute phase the fundus shows a hyperemic disc with telangiectatic microangiopathy and no leakage on angiography.

**Tests**
Genetic testing for the mitochondrial DNA variants in blood; visual fields; electrocardiogram (pre-excitation).

**Imaging**
Optical coherence tomography (nerve fibre layer thickening, then thinning); orbit and brain MRI to rule out compression or demyelination.

## Treatment

**Medical**
Idebenone, a coenzyme Q analogue that can pass electrons to complex III; approved in some countries, with modest benefit if started early.

**Lifestyle**
Avoiding tobacco and heavy alcohol, which raise the risk of vision loss in carriers.

**Rehabilitation**
Visual rehabilitation and low-vision aids.

**Follow-up**
Eye follow-up with visual fields and optical coherence tomography; maternal genetic counselling.

## Complications

- Permanent legal blindness
- Optic atrophy
- Pre-excitation arrhythmias
- A multiple sclerosis-like illness in some women

## Prognosis

Most are left with severe low vision; the m.14484T>C (MT-ND6) variant has the best chance of partial recovery.

## Prevention

- Genetic counselling for the maternal family
- Avoiding tobacco and alcohol in carriers

## Test yourself

Think of the answer, then tap the question to see it.

## Which respiratory chain complex is affected in Leber hereditary optic neuropathy?

Complex I: the variants lie in MT-ND genes of mitochondrial DNA.

## What is the most common LHON variant?

m.11778G>A in MT-ND4.

## Why are retinal ganglion cells so vulnerable?

Their axons are long and unmyelinated inside the eye; they spend a lot of energy and depend on complex I.

## How does LHON differ from optic neuritis?

LHON is painless, affects both eyes in sequence and is maternally inherited; optic neuritis usually hurts on eye movement.

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## Related conditions

- [MELAS (mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes)](https://durgical.com/en/conditions/melas/)
- [Leigh syndrome](https://durgical.com/en/conditions/leigh-syndrome/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Leber hereditary optic neuropathy: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/leber-hereditary-optic-neuropathy/) (MedlinePlus, US National Library of Medicine, 2026); [MT-ND4 gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/mt-nd4/) (MedlinePlus, US National Library of Medicine, 2026); [MT-ND1 gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/mt-nd1/) (MedlinePlus, US National Library of Medicine, 2026).

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Source: https://durgical.com/en/conditions/leber-hereditary-optic-neuropathy/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/leber-hereditary-optic-neuropathy/